Lens array, method for manufacturing lens array, electro-optical device, and electronic apparatus

ABSTRACT

A lens array including a base which has a plurality of concave sections. The concave sections are arranged in a first direction, a second direction which is orthogonal or almost orthogonal with the first direction, and a third direction which intersects with the first direction and the second direction. A thickness of the base between the concave sections arranged with the first direction or the second direction is thinner than a thickness of the base between the concave sections arranged with the third direction.

The present application is a continuation of U.S. patent applicationSer. No. 14/599,586 filed Jan. 19, 2015 which claims priority fromJapanese Patent Application No. 2014-010151 filed Jan. 23, 2014, each ofwhich are expressly incorporated by reference herein.

BACKGROUND

1. Technical Field

The present invention relates to a lens array, a method formanufacturing a lens array, an electro-optical device, an electronicapparatus, and the like.

2. Related Art

Electro-optical devices which are provided with an electro-opticalmaterial such as a liquid crystal between an element substrate and acounter substrate are known. Examples of electro-optical devices includeliquid crystal devices, which are used as a liquid crystal light bulb ina projector, and the like. There is a demand for realizing high lightutilization efficiency in such liquid crystal devices.

A liquid crystal device is provided with TFT elements which drive pixelelectrodes, wiring, and the like in pixels on an element substrate and alight shielding layer is provided so as to be planarly overlappedtherewith. Due to this, a portion of incident light is shielded by thelight shielding layer and not used. Therefore, as described inJP-A-2004-70282, a configuration is known which improves lightutilization efficiency by concentrating incident light with microlensesby providing a microlens array in which microlenses are arranged in atleast one of an element substrate and a counter substrate in a liquidcrystal device.

However, there is a problem that light utilization efficiency is poor inthe microlens array according to JP-A-2004-70282. A solid angle of aluminous flux which is output from the liquid crystal device may belarge even when the liquid crystal device is provided with the microlensarray. When a liquid crystal device which is provided with such amicrolens array is used as a liquid crystal light bulb of a projector, awide angle of light which is output from a liquid crystal device mayexceed an angle of incidence regulated by an F value of a projectorlens. In this case, a portion of light which is output from the liquidcrystal device is not incident on the projector lens and as a result,the amount of light which is projected on a screen decreases. Thisproblem is serious, especially in the microlens array according toJP-A-2004-70282, and even when a microlens array is used, improvement inthe brightness is limited.

In other words, the microlens array of the related art has a problem inthat it is difficult to sufficiently increase the light utilizationefficiency.

SUMMARY

The invention can be realized in the following forms or applicationexamples.

Application Example 1

A lens array according to this application example includes a base whichhas a first concave section, and a first lens which covers the firstconcave section, in which the first concave section includes a surfacewhich inclines from a surface of the base.

Application Example 2

In the lens array according to Application Example 1, a first lens mayinclude a first region, and a second region and a third region which arearranged to continue from the first region in a periphery of the firstregion.

In addition, the second region may include a cylindrical lens and thethird region may include a spherical lens.

Application Example 3

A lens array according to this application example includes a base whichhas a first concave section, and a first lens which covers the firstconcave section, in which the first lens includes a first region, and asecond region and a third region which are arranged to continue from thefirst region in a periphery of the first region, the second regionincludes a cylindrical lens, and the third region includes a sphericallens.

Application Example 4

In the lens array according to Application Example 2, light which isincident on the first region may go substantially straight, a light pathof light which is incident on the second region may be bent to the firstregion side, and a light path of light which is incident on the thirdregion may be bent to the first region side.

Application Example 5

In the lens array according to Application Example 1 or 2, an anglebetween a surface and the inclined surface may be in a range from 35° to53°.

Application Example 6

The lens array according to any one of Application Examples 1 to 5 mayfurther include a second lens which covers a second concave section ofthe base and a third lens which covers a third concave section of thebase, in which the first concave section and the second concave sectionmay be arranged to be adjacent in a first direction, the second concavesection and the third concave section may be arranged to be adjacent ina second direction which intersects with the first direction, and athickness of the base at a boundary between the first concave sectionand the second concave section may be thinner than a thickness of thebase between the first concave section and the third concave section.

Application Example 7

In the lens array according to Application Example 6, each of the firstlens, the second lens, and the third lens may respectively include afirst region, and a second region and a third region which are arrangedto continue from the first region in the periphery of the first region,the second region of the first lens and the second region of the secondlens may be continuous, and the third region of the first lens and thethird region of the third lens may be separated.

Application Example 8

In the lens array according to Application Example 7, the second regionmay include a cylindrical lens and the third region may include aspherical lens.

Application Example 9

A method for manufacturing a lens array according to this applicationexample includes forming a base which has a first concave section, andforming a first lens which covers the first concave section, in whichthe first concave section includes a surface which inclines from asurface of the base.

Application Example 10

A method for manufacturing a lens array according to this applicationexample includes forming a base which has a first concave section, andforming a first lens which covers the first concave section, in whichthe first lens includes a first region, and a second region and a thirdregion which are arranged to continue from the first region in aperiphery of the first region, the second region includes a cylindricallens, and the third region includes a spherical lens.

Application Example 11

An electro-optical device includes the lens array according to any oneof Application Examples 1 to 8.

According to this configuration, it is possible to realize anelectro-optical device in which light utilization efficiency is high anda bright display is possible.

Application Example 12

An electro-optical device includes a lens array which is manufactured bythe method for manufacturing a lens array according to ApplicationExample 9 or 10.

According to this configuration, it is possible to realize anelectro-optical device in which light utilization efficiency is high anda bright display is possible.

Application Example 13

An electronic apparatus includes the electro-optical device according toApplication Example 11 or 12.

According to this configuration, it is possible to realize an electronicapparatus which is provided with an electro-optical device in whichlight utilization efficiency is high and a bright display is possible.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a schematic planar diagram which shows a configuration of aliquid crystal device according to Embodiment 1.

FIG. 2 is an equivalent circuit diagram which shows an electricalconfiguration of the liquid crystal device according to Embodiment 1.

FIG. 3 is a schematic cross-sectional diagram which shows aconfiguration of the liquid crystal device according to Embodiment 1.

FIG. 4 is a planar diagram which illustrates a configuration of amicrolens according to Embodiment 1.

FIG. 5 is a planar diagram which illustrates the microlens according toEmbodiment 1.

FIGS. 6A and 6B are cross-sectional diagrams which show a configurationof the microlens according to Embodiment 1.

FIGS. 7A to 7C are diagrams which illustrate light utilizationefficiency in an electro-optical device.

FIG. 8 is a diagram which illustrates light utilization efficiency inthe microlens according to Embodiment 1.

FIGS. 9A to 9D are schematic cross-sectional diagrams which show amethod for manufacturing the microlens array according to Embodiment 1.

FIGS. 10A to 10C are schematic cross-sectional diagrams which show amethod for manufacturing the microlens array according to Embodiment 1.

FIG. 11 is a schematic diagram which shows a configuration of aprojector as an electronic apparatus according to Embodiment 1.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Outline

A microlens array of one aspect of the invention includes a base whichhas a first concave section and a first microlens which covers the firstconcave section, in which the first concave section includes a surfacewhich inclines from a surface of the base.

Detailed description will be given below; however, by arranging themicrolens to cover a surface which inclines from a surface of the base,it is possible to suppress variations in the angle of light which passesthrough the microlens and is incident on a liquid crystal and it ispossible to increase the light utilization efficiency.

It is preferable that the angle between the surface and the inclinedsurface be in a range from 35° to 53°.

Example 1

A microlens array according to the present example is provided with acylindrical lens and a spherical lens which are arranged in a cell, inwhich the cell has at least sides, a corner section, a first region, asecond region, and a third region, the second region is arranged betweenthe first region and the sides, the third region is arranged between thefirst region and the corner section, the cylindrical lens is formed inthe second region, and the spherical lens is formed in the third region.

According to this configuration, since light which is incident on asurrounding section of the microlens is concentrated by the cylindricallens and the spherical lens, it is possible to realize a microlens arrayin which the light utilization efficiency is high.

Example 2

In the microlens array according to example 1 described above, it ispreferable that incident light which is incident on the first region andin parallel with a normal line of the cell be substantially straight, alight path of incident light which is incident on the second region andin parallel with a normal line of the cell be bent to the first regionside by the cylindrical lens, and a light path of incident light whichis incident on the third region and in parallel with a normal line ofthe cell be bent to the first region side by the spherical lens.

According to this configuration, since light which is incident on thecentral section of the microlens is straight and light which is incidenton the surrounding section of the microlens is concentrated by thecylindrical lens and the spherical lens, it is possible to realize amicrolens array in which the light utilization efficiency is high.

Example 3

In the microlens array according to example 1 or 2 described above, itis preferable that the sides include a first side, a second side, athird side, and a fourth side, the corner section include a first cornersection, a second corner section, a third corner section, and a fourthcorner section, the second region include a first second region, asecond second region, a third second region, and a fourth second region,and the third region include a first third region, a second thirdregion, a third third region, and a fourth third region.

According to this configuration, since four cylindrical lenses and fourspherical lenses are arranged in the surrounding section of themicrolens, it is possible to realize a microlens array in which thelight utilization efficiency is high.

Example 4

A microlens array according to the present example is provided with acylindrical lens and a spherical lens which are arranged in a cell, inwhich the cell has a first region, a second region, and a third region,a boundary between the first region and the second region is a straightline, a boundary between the first region and the third region is anintersection, the cylindrical lens is formed in the second region, andthe spherical lens is formed in the third region.

According to this configuration, since light which is incident on asurrounding section of the microlens is concentrated by the cylindricallens and the spherical lens, it is possible to realize a microlens arrayin which the light utilization efficiency is high.

Example 5

In the microlens array according to the example 4 described above, it ispreferable that incident light which is incident on the first region andin parallel with a normal line of the cell be substantially straight, alight path of incident light which is incident on the second region andin parallel with a normal line of the cell be bent to the first regionside by the cylindrical lens, and a light path of incident light whichis incident on the third region and in parallel with a normal line ofthe cell be bent to the first region side by the spherical lens.

According to this configuration, since light which is incident on thecentral section of the microlens is straight and light which is incidenton the surrounding section of the microlens is concentrated by thecylindrical lens and the spherical lens, it is possible to realize amicrolens array in which the light utilization efficiency is high.

Example 6

In the microlens array according to example 4 or 5 described above, itis preferable that the second region include a first second region and asecond second region, a boundary between the first region and the firstsecond region be a first straight line, a boundary between the firstregion and the second second region be a second straight line, and thefirst straight line and the second straight line intersect at theintersection.

According to this configuration, since a plurality of cylindrical lensesand a plurality of spherical lenses are arranged in the surroundingsection of the microlens, it is possible to realize a microlens array inwhich the light utilization efficiency is high.

A microlens of another aspect of the invention further includes a secondmicrolens which covers a second concave section of the base and a thirdmicrolens which covers a third concave section of the base, in which thefirst concave section and the second concave section are arranged to beadjacent in a first direction, the second concave section and the thirdconcave section are arranged to be adjacent in a second direction whichintersects with the first direction, and a thickness of the base at aboundary between the first concave section and the second concavesection is thinner than a thickness of the base between the firstconcave section and the third concave section.

According to this configuration, it is possible to efficiently arrangethe microlens and it is possible to increase the light utilizationefficiency.

A method for manufacturing a microlens array of one aspect of theinvention includes forming a base which has a first concave section, andforming a first microlens which covers the first concave section, inwhich the first concave section includes a surface which inclines from asurface of the base.

A method for manufacturing a microlens array of another aspect of theinvention includes forming a base which has a first concave section, andforming a first microlens which covers the first concave section, inwhich the first microlens includes a first region, and a second regionand a third region which are arranged to continue from the first regionin a periphery of the first region, the second region includes acylindrical lens, and the third region includes a spherical lens.

According to these manufacturing methods, it is possible to manufacturethe microlens described above.

Example 7

A method for manufacturing a microlens array according to the presentexample includes forming a first transparent material on a substrate,forming a mask layer which has an opening section in a unit region ofthe first transparent material, forming a concave section in the firsttransparent material by carrying out isotropic etching on the firsttransparent material via the mask layer, and filling the concave sectionwith a second transparent material which has a refractive index which isdifferent from the refractive index of the first transparent material,in which the opening section is a polygon in plan view.

According to this method, since light which is incident on a site whichcorresponds to the opening section of the microlens in plan view isstraight, light which is incident on the outside along sides of theopening section of the microlens in plan view is concentrated by acylindrical lens, and light which is incident on the outside of a cornerof the opening section of the microlens in plan view is concentrated bya spherical lens, it is possible to realize a microlens array in whichthe light utilization efficiency is high.

Example 8

In the method for manufacturing a microlens array according to example 7described above, it is preferable that at least one side which forms theunit region and at least one side which forms the opening section besubstantially in parallel in plan view.

According to this method, since it is possible to make the shape of themicrolens in plan view and the shape of the unit region uniform, it ispossible to realize a microlens array in which the light utilizationefficiency is high.

Below, description will be given of an embodiment which embodies theinvention with reference to diagrams. The diagrams which are used aredisplayed by being appropriately enlarged, reduced, or magnified suchthat the portion to be illustrated is in a recognizable state. Inaddition, there are cases in which configuration elements other than theconstituent elements which are necessary for the description are omittedfrom the diagrams.

Here, in the forms below, for example, a case of being described as “ona substrate” represents a case of being arranged so as to come intocontact with the top of the substrate, a case of being arranged on thesubstrate via another component, or a case of being arranged such that aportion comes into contact with the top of the substrate and a portionis arranged via another component.

Embodiment 1

Electro-Optical Device

Here, description will be given with an active matrix type liquidcrystal device which is provided with a thin film transistor (TFT) as aswitching element of a pixel as an example of an electro-optical device.The liquid crystal device is able to be favorably used, for example, asan optical modulator (a liquid crystal light bulb) of a projection typedisplay apparatus (a projector) which will be described below.

FIG. 1 is a schematic planar diagram which shows a configuration of aliquid crystal device according to Embodiment 1. FIG. 2 is an equivalentcircuit diagram which shows an electrical configuration of the liquidcrystal device according to Embodiment 1. FIG. 3 is a schematiccross-sectional diagram which shows a configuration of the liquidcrystal device according to Embodiment 1, in detail, a partial schematiccross-sectional diagram taken along line III-III in FIG. 1. Firstly,description will be given of a liquid crystal device 1 according toEmbodiment 1 with reference to FIG. 1, FIG. 2, and FIG. 3.

As shown in FIG. 1 and FIG. 3, the liquid crystal device 1 according toEmbodiment 1 is provided with an element substrate 20 as a firstsubstrate, a counter substrate 30 as a second substrate which isarranged to oppose the element substrate 20, a sealing material 42, anda liquid crystal 40 as an electro-optical material. The elementsubstrate 20 and the counter substrate 30 are arranged to oppose eachother. As shown in FIG. 1, the element substrate 20 is larger than thecounter substrate 30 and both of the substrates are bonded via thesealing material 42 which is arranged in a frame shape along an edgesection of the counter substrate 30.

As shown in FIG. 1, the liquid crystal 40 is held in a space which issurrounded by the element substrate 20, the counter substrate 30, andthe sealing material 42 and has a positive or negative dielectricanisotropy. The sealing material 42 is, for example, formed of anadhesive agent such as a thermosetting or ultraviolet curable epoxyresin. A spacer (which is not shown in the diagram) for maintaining aconstant interval between the element substrate 20 and the countersubstrate 30 is mixed in the sealing material 42.

A light shielding layer 22, a light shielding layer 26, or a lightshielding layer 32 as a light shielding section which has a frame shapedperiphery section is provided inside the sealing material 42 which isarranged in a frame shape. The light shielding layer 22, the lightshielding layer 26, or the light shielding layer 32 is, for example,formed of a light shielding metal, metal oxide, or the like. The insideof the light shielding layer 22, the light shielding layer 26, or thelight shielding layer 32 is a display region E in which a plurality ofpixels P are arranged. The pixels P have, for example, a substantiallyrectangular shape and are arranged in a matrix.

The display region E is a region which substantially contributes to thedisplay in the liquid crystal device 1. As shown in FIG. 3, the lightshielding layer 22 a and the light shielding layer 26 a are provided,for example, in a grid pattern in the display region E at a boundarysection of each of the pixels P so as to planarly partition the pixelsP. Here, the liquid crystal device 1 may be provided with a dummy regionwhich is provided so as to surround the periphery of the display regionE and which substantially does not contribute to the display.

A data line driving circuit 51 and a plurality of external connectingterminals 54 are provided along a first periphery side on the oppositeside to the display region E of the sealing material 42 which is formedalong the first periphery side of the element substrate 20. In addition,an inspection circuit 53 is provided on the display region E side of thesealing material 42 along another second periphery side which opposesthe first periphery side. Furthermore, a scan line driving circuit 52 isprovided inside the sealing material 42 along the other two peripherysides which are orthogonal with the above two periphery sides and opposeeach other.

A plurality of wirings 55 which connect two scan line driving circuits52 are provided on the display region E side of the sealing material 42of the second periphery side where the inspection circuit 53 isprovided. The wiring which is connected to the data line driving circuit51 and the scan line driving circuit 52 is connected with a plurality ofexternal connecting terminals 54. In addition, vertical conductionsections 56 for creating electrical conduction between the elementsubstrate 20 and the counter substrate 30 are provided in four cornersof the counter substrate 30. Here, the arrangement of the inspectioncircuit 53 is not limited to this configuration and the inspectioncircuit 53 may be provided at a position along the inside of the sealingmaterial 42 between the data line driving circuit 51 and the displayregion E.

In the description below, a direction along the first periphery sidewhere the data line driving circuit 51 is provided is set as a firstdirection (an X direction) and a direction which is orthogonal with thefirst periphery side is set as a second direction (a Y direction). The Xdirection is a direction which is in parallel with line III-III inFIG. 1. Black matrixes along the X direction and the Y direction areprovided in a grid pattern in the element substrate 20 by the lightshielding layer 22 a and the light shielding layer 26 a (refer to FIG.3). Accordingly, the pixels P are partitioned in a grid pattern by theblack matrixes formed of the light shielding layer 22 a and the lightshielding layer 26 a and a region which does not overlap with the lightshielding layer 22 a and the light shielding layer 26 a in plan view inthe pixels P is an opening region (an optical modulation section) in thepixels P.

Here, a direction which is orthogonal with the X direction and the Ydirection and toward the upper part in FIG. 1 is set as a Z direction.In the present specification, the view from a normal line direction (theZ direction) of the counter substrate 30 side surface of the liquidcrystal device 1 is referred to as a “plan view”.

As shown in FIG. 2, in the display region E, a scan line 2 and a dataline 3 are formed so as to intersect with each other and the pixels Pare provided in correspondence with the intersection between the scanline 2 and the data line 3. A pixel electrode 28 and a TFT 24, which isa switching element, are provided in each of the pixels P.

One of source drains of the TFT 24 is electrically connected with thedata line 3 which extends from the data line driving circuit 51. Imagesignals S1, S2, . . . , Sn are supplied from the data line drivingcircuit 51 (refer to FIG. 1) to the data line 3. A gate of the TFT 24 iselectrically connected with a portion of the scan line 2 which extendsfrom the scan line driving circuit 52. Scan signals G1, G2, . . . , Gmare supplied from the scan line driving circuit 52 to the scan line 2.The other source drain of the TFT 24 is electrically connected with thepixel electrode 28.

The image signals S1, S2, . . . , Sn are written in the pixel electrode28 via the data line 3 at a predetermined timing by setting the TFT 24to an on state only in a set period. A storage capacitor 5 is formedbetween a capacitor line 4 which is formed along the scan line 2 and thepixel electrode 28 in the pixel P in order to maintain the image signalsS1, S2, . . . , Sn which are supplied to the pixel electrode 28. Thestorage capacitor 5 is arranged to line up with a liquid crystalcapacitor. Thus, when a voltage which corresponds to the image signalsS1, S2, . . . , Sn is applied to the liquid crystal 40 (refer to FIG. 3)of each of the pixels P, the oriented state of the liquid crystal 40changes due to the applied voltage, light which is incident on theliquid crystal 40 is modulated, and it is possible to displaygradations.

As shown in FIG. 3, the liquid crystal device 1 has the elementsubstrate 20 and the counter substrate 30, and the counter substrate 30is further provided with a microlens array 10, a light path lengthadjusting layer 31, the light shielding layer 32, a protective layer 33,a common electrode 34, and an oriented film 35. Here, cross-sections forfive pixels are drawn in FIG. 3 in order to make the description easy tounderstand.

The microlens array 10 is provided with a first transparent material 11and a second transparent material 13. The first transparent material 11and the second transparent material 13 are materials which havedifferent refractive indexes from each other and transmit light.

The first transparent material 11 is formed of an inorganic materialwhich has a light transmitting property such as a silicon oxide film(SiO_(X), X is a value of 1 or 2). Since the silicon oxide film isharmless, excellent in transparency, and easily manufactured andprocessed, it is possible for the first transparent material to be amaterial which is harmless, excellent in translucency, and easilymanufactured and processed. The refractive index of the silicon oxidefilm which forms the first transparent material 11 is in a range from1.46 to 1.50. In the present embodiment, the first transparent material11 is a quartz substrate and is the substrate of the counter substrate30. When a surface on the liquid crystal 40 side of the firsttransparent material 11 is set as an upper surface 11 a, a plurality ofconcave sections 12 are formed from the upper surface 11 a of the firsttransparent material 11 and the surfaces of the concave sections 12 area portion of the interface between the first transparent material 11 andthe second transparent material 13. Each of the concave sections 12configures a cell CL (refer to FIG. 4) of the microlens array 10 and thecells CL are provided in correspondence with the pixels P in theelectro-optical device. The concave section 12 has a flat section 12 awhich is arranged in the central portion thereof and a curved surfacesection 12 b and a periphery section 12 c which are arranged in theperiphery of the flat section 12 a (refer to FIGS. 6A and 6B). Detaileddescription will be given below of the shape of the concave section 12.

The second transparent material 13 is formed so as to cover the firsttransparent material 11 and fill in the concave section 12. The secondtransparent material 13 is formed of a material which has a lighttransmitting property and a different refractive index from the firsttransparent material 11. In more detail, the second transparent material13 is formed of an inorganic material which has a higher refractiveindex than the first transparent material 11. Examples of such aninorganic material include a silicon oxynitride film (SiON), a siliconnitride film (SiN), an alumina film (Al₂O₃), and the like and apreferable refractive index thereof is approximately 1.60. Since thesilicon oxynitride film or the silicon nitride film are harmless,excellent in transparency, and easily manufactured and processed, it ispossible for the second transparent material to be a material which isharmless, excellent in transparency, and easily manufactured andprocessed. In the present embodiment, the silicon oxynitride film isused as the second transparent material 13. A microlens ML with a convexshape is configured by the concave sections 12 being filled with thesecond transparent material 13. Detailed description will be given belowof a method for manufacturing the microlens ML.

The thickness of the second transparent material 13 is formed to bethicker than the depth of the concave section 12 and the surface of thesecond transparent material 13 is a substantially flat surface. That is,the second transparent material 13 has a portion which configures themicrolens ML by filling the concave sections 12 and a portion whichfulfills a role of a planarizing layer which covers the upper surface ofthe first transparent material 11 and the surface of the microlens ML.The flat surface of the second transparent material 13 and the flatsection 12 a of the concave section 12 are substantially parallel. Here,in a case of using the wording “substantially parallel”, “substantiallymatched”, “substantially equal”, or the like in the presentspecification, these have meanings of being in parallel in terms of thedesign concept, being matched in terms of the design concept, beingequal in terms of the design concept, and the like and cases of beingdifferent due to errors in manufacturing, errors in measurement, minutedifferences, or the like are also included.

The light path length adjusting layer 31 is provided so as to cover themicrolens array 10. The light path length adjusting layer 31 transmitslight and is, for example, formed of an inorganic material which hassubstantially the same refractive index as the first transparentmaterial 11. The light path length adjusting layer 31 is set to adjust adistance from the microlens ML to the light shielding layer 26 a andsuch that light which is concentrated in the microlens ML passes throughthe opening region of the pixel P without being shielded by the lightshielding layer 26 a or the light shielding layer 22 a. Accordingly, thethickness of the light path length adjusting layer 31 is appropriatelyset based on optical conditions such as a focal point distance of themicrolens ML according to the wavelength of light.

The light shielding layer 32 is provided on the light path lengthadjusting layer 31 (the liquid crystal 40 side). The light shieldinglayer 32 is formed in a frame shape so as to overlap the light shieldinglayer 22 and the light shielding layer 26 of the element substrate 20 inplan view. The region which is surrounded by the light shielding layer32 (the display region E) is a region in which it is possible for lightto be transmitted. Here, a light shielding layer which is not shown inthe diagram and using the same material as the light shielding layer 32may be further provided on the light path length adjusting layer 31which overlaps the light shielding layer 22 a and the light shieldinglayer 26 a in plan view. The light shielding layer which is not shown inthe diagram is arranged in corners of each of the pixels P or in theperiphery of each of the pixels P, reflects light, which falls on thelight shielding layer 22 a or the light shielding layer 26 a on theelement substrate 20 side without being completely concentrated in themicrolens ML, on the counter substrate 30 side and has an effect thatprevents increases in the temperature of the liquid crystal device 1.

The protective layer 33 is provided so as to cover the light path lengthadjusting layer 31 and the light shielding layer 32. The commonelectrode 34 is provided so as to cover the protective layer 33. Thecommon electrode 34 is formed over a plurality of the pixels P. Thecommon electrode 34 is, for example, formed of a transparent conductivefilm such as indium tin oxide (ITO) or indium zinc oxide (IZO). Theoriented film 35 is provided so as to cover the common electrode 34.

Here, the protective layer 33 covers the light shielding layer 32 andplanarizes the liquid crystal 40 side surface of the common electrode34, but is not an essential constituent element. Accordingly, forexample, the configuration may be a configuration in which the commonelectrode 34 directly covers the conductive light shielding layer 32.

The element substrate 20 is provided with a substrate 21, the lightshielding layer 22, the light shielding layer 22 a, an insulation layer23, the TFT 24, an insulation layer 25, the light shielding layer 26,the light shielding layer 26 a, an insulation layer 27, the pixelelectrode 28, and an oriented film 29. The substrate 21 is, for example,formed of a material which transmits light such as glass, quartz, andthe like or includes such a material.

The light shielding layer 22 and the light shielding layer 22 a areprovided on the substrate 21. The light shielding layer 22 is formed ina frame shape so as to overlap the light shielding layer 26 on the upperlayer in plan view. The light shielding layer 22 a and the lightshielding layer 26 a are arranged so as to interpose the TFT 24therebetween in the thickness direction (the Z direction) of the elementsubstrate 20. The light shielding layer 22 a and the light shieldinglayer 26 a overlap with at least a channel forming region of the TFT 24in plan view. By the light shielding layer 22 a and the light shieldinglayer 26 a being provided, the incidence of light on the TFT 24 issuppressed. The region which is surrounded by the light shielding layer22 a and the light shielding layer 26 a in plan view is an openingregion of the pixel P and is a region in which light is transmitted inthe pixel P.

The insulation layer 23 is provided so as to cover the substrate 21, thelight shielding layer 22, and the light shielding layer 22 a. Theinsulation layer 23 is, for example, formed of an inorganic materialsuch as SiO₂.

The TFT 24 is provided on the insulation layer 23. The TFT 24 is aswitching element which drives the pixel electrode 28. The TFT 24includes a semiconductor layer, a gate electrode, a source electrode,and a drain electrode which are not shown in the diagram. A source, achannel forming region, and a drain are formed in the semiconductorlayer. A lightly doped drain (LDD) region may be formed in the interfacebetween the channel forming region and the source or between the channelforming region and the drain.

The gate electrode is formed in the element substrate 20 in the regionwhich overlaps with the channel forming region of the semiconductorlayer in plan view via a portion of the insulation layer 25 (a gateinsulation film). Although omitted from the diagram, the gate electrodeis electrically connected with a scan line which is arranged on thelower layer side via a contact hole and controls the TFT 24 to be on oroff by applying a scan signal.

The insulation layer 25 is provided so as to cover the insulation layer23 and the TFT 24. The insulation layer 25 is, for example, formed of aninorganic material such as SiO₂. The insulation layer 25 includes a gateinsulation film which insulates between the semiconductor layer and thegate electrode of the TFT 24. Due to the insulation layer 25, surfaceunevenness caused by the TFT 24 is eased. The light shielding layer 26and the light shielding layer 26 a are provided on the insulation layer25. Then, for example, the insulation layer 27 formed of an inorganicmaterial is provided so as to cover the insulation layer 25, the lightshielding layer 26, and the light shielding layer 26 a.

The pixel electrode 28 is provided for each pixel P on the insulationlayer 27. The pixel electrode 28 is arranged so as to overlap theopening region of the pixel P in plan view and the edge section of thepixel electrode 28 overlaps with the light shielding layer 22 a or thelight shielding layer 26 a. The pixel electrode 28 is, for example,formed of a transparent conductive film such as ITO or IZO. The orientedfilm 29 is provided so as to cover the pixel electrode 28. The liquidcrystal 40 is held between the oriented film 29 of the element substrate20 and the oriented film 35 of the counter substrate 30.

Here, the TFT 24 and an electrode, a wiring, or the like (which is notshown in the diagram) which supplies an electrical signal to the TFT 24are provided in a region which overlaps the light shielding layer 22 orthe light shielding layer 22 a and the light shielding layer 26 or thelight shielding layer 26 a in plan view. The configuration may be aconfiguration in which the electrode, the wiring, or the like serves asthe light shielding layer 22 or the light shielding layer 22 a and thelight shielding layer 26 or the light shielding layer 26 a.

In the liquid crystal device 1 according to Embodiment 1, for example,light which is emitted from a light source or the like is incident fromthe counter substrate 30 side which is provided with the microlens MLand is concentrated by the microlens ML. Out of light which is incidenton the microlens ML along a normal line direction of the upper surface11 a from the first transparent material 11 side, incident light L1which is incident on the central portion of the microlens ML in planview (the flat section 12 a of the concave section 12) goes straightthrough the microlens ML as is, passes through the liquid crystal 40,and is output to the element substrate 20 side.

On the other hand, incident light L2 which is incident on thesurrounding section of the microlens ML in plan view (a region whichoverlaps with the light shielding layer 22 a or the light shieldinglayer 26 a in plan view) is shielded by the light shielding layer 26 orthe light shielding layer 26 a as shown with a dashed line ifin a caseof going straight as is. However, in the electro-optical device of thepresent embodiment, the incident light L2 is concentrated to the planarcentral side of the pixel P in the microlens ML (refraction due to therefractive index difference between the first transparent material 11and the second transparent material 13). In the liquid crystal device 1,the light incident on the boundary between microlenses ML is also madeto be incident inside the opening region of the pixel P due to aconcentration effect in the boundary in this manner and is able to passthrough the liquid crystal 40. As a result, the amount of light which isoutput from the element substrate 20 side increases and the lightutilization efficiency is increased.

Microlens

Subsequently, description will be given of a configuration and an actionof the microlens ML with which the microlens array 10 according toEmbodiment 1 is provided with reference to FIG. 4, FIG. 5, and FIGS. 6Aand 6B. FIG. 4 is a planar diagram which illustrates a configuration ofthe microlens according to Embodiment 1. FIG. 5 is a planar diagramwhich illustrates the microlens according to Embodiment 1. FIGS. 6A and6B are cross-sectional diagrams which show a configuration of themicrolens according to Embodiment 1, FIG. 6A is a cross-sectionaldiagram taken along line VIA-VIA in FIG. 4 or FIG. 5, and FIG. 6B is across-sectional diagram taken along line VIB-VIB in FIG. 4 or FIG. 5.

The microlens array 10 is provided with a plurality of cells CL and theplurality of the cells CL are arranged in a matrix such that the cellsCL which are adjacent in the X direction and the Y direction come intocontact with each other. In a case in which the microlens array 10 isassembled in the electro-optical device, the cells CL of the microlensarray 10 and the pixels P of the electro-optical device are aligned soas to substantially match in plan view. Here, one cell CL whichconfigures the microlens array 10 is drawn in FIG. 4 and FIG. 5. Inaddition, although not shown in FIG. 4 or FIG. 5, in a case in which themicrolens array 10 is assembled in the electro-optical device, the lightshielding layer 22 a or the light shielding layer 26 a is arranged inthe element substrate 20 so as to be along the boundary of the cells CLwhich are adjacent in the X direction and the Y direction.

As shown in FIG. 4, the cell CL has a polygonal planar shape. The cellCL is a quadrilateral and a square in the present embodiment; however,the cell CL may be a rectangle or may be a triangle or a hexagon. Theplanar shape of the cell CL is able to be matched with the planar shapeof the pixel P.

As shown in FIG. 4, the cell CL has at least a side which is a boundaryof the cell CL (a cell boundary side), a corner section where the cellboundary sides intersect (a cell corner section), a first region A1, asecond region, and a third region. The first region A1 is arranged inthe central portion of the cell CL and the second region and the thirdregion are arranged outside the first region A1 and in the surroundingsection of the cell CL. That is, the second region is arranged betweenthe first region A1 and the cell boundary side and the third region isarranged between the first region A1 and the cell corner section. Theboundary between the first region A1 and the second region is a straightline and the boundary between the first region A1 and the third regionis an intersection.

Since the cell CL is a quadrilateral in the present embodiment, indetail, the cell boundary side includes a first cell boundary side CB1,a second cell boundary side CB2, a third cell boundary side CB3, and afourth cell boundary side CB4, and the cell corner section includes afirst cell corner section CC1, a second cell corner section CC2, a thirdcell corner section CC3, and a fourth cell corner section CC4. Inaddition, the second region includes a first second region A2-1, asecond second region A2-2, a third second region A2-3, and a fourthsecond region A2-4, and the third region includes a first third regionA3-1, a second third region A3-2, a third third region A3-3, and afourth third region A3-4.

As an example, the first region A1 is a polygon in plan view. It is morepreferable that the first region A1 be smaller than the cell CL and be apolygon which is similar to the cell CL and that at least one side whichforms the cell CL and at least one side which forms the first region A1be substantially parallel in plan view. In this manner, since it ispossible to make a shape of the microlens in plan view and a shape ofthe cell CL uniform apart from the cell corner section, it is possibleto realize the microlens array 10 in which the light utilizationefficiency is high. That is, the side which is a boundary of themicrolens ML matches the cell boundary side. In the present embodiment,the first region A1 is a quadrilateral and a square. In addition, thecenter of the cell CL in plan view (a center of gravity of the planarshape body of the cell CL) and a center of the first region A1 in planview (a center of gravity of the planar shape body of the first regionA1) are substantially matched.

A boundary between the first region A1 and the first second region A2-1is a first straight line (a first region boundary AB1), a boundarybetween the first region A1 and the second second region A2-2 is asecond straight line (a second region boundary AB2), a boundary betweenthe first region A1 and the third second region A2-3 is a third straightline (a third region boundary AB3), and a boundary between the firstregion A1 and the fourth second region A2-4 is a fourth straight line (afourth region boundary AB4). Each of the region boundaries intersects atan intersection. In detail, the first straight line (the first regionboundary AB1) and the second straight line (the second region boundaryAB2) intersect at the first intersection AC1, the second straight line(the second region boundary AB2) and the third straight line (the thirdregion boundary AB3) intersect at the second intersection AC2, the thirdstraight line (the third region boundary AB3) and the fourth straightline (the fourth region boundary AB4) intersect at the thirdintersection AC3, and the fourth straight line (the fourth regionboundary AB4) and the first straight line (the first region boundaryAB1) intersect at the fourth intersection AC4.

Accordingly, the first second region A2-1 is positioned between thefirst region boundary AB1 and the first cell boundary side CB1 in thefirst region A1, the second region A2-2 is positioned between the secondregion boundary AB2 and the second cell boundary side CB2 in the firstregion A1, the third second region A2-3 is positioned between the thirdregion boundary AB3 and the third cell boundary side CB3 in the firstregion A1, and the fourth second region A2-4 is positioned between thefourth region boundary AB4 and the fourth cell boundary side CB4 in thefirst region A1. In addition, the first third region A3-1 is positionedbetween the first intersection AC1 and the first cell corner section CC1in the first region A1, the second third region A3-2 is positionedbetween the second intersection AC2 and the second cell corner sectionCC2 in the first region A1, the third region A3-3 is positioned betweenthe third intersection AC3 and the third cell corner section CC3 in thefirst region A1, and the fourth third region A3-4 is positioned betweenthe fourth intersection AC4 and the fourth cell corner section CC4 inthe first region A1.

As an example, arrangement is carried out such that a non-lens section,a cylindrical lens, and a spherical lens are included in the cell CL. Indetail, the non-lens section is formed in the first region A1, thecylindrical lens is formed in the second region, and the spherical lensis formed in the third region.

The first region A1 is a flat section 12 a shown in FIG. 3 and theincident light which is incident on the first region A1 and in parallelwith the normal line of the cell CL is substantially straight as is.

The light path of the incident light which is incident on the secondregion and in parallel with the normal line of the cell CL is bent tothe first region A1 side by the cylindrical lens. The cylindrical lensis a lens which converges or disperses incident light by havingrefractive power in one direction and which does not have refractivepower in the other direction which intersects orthogonally with thisdirection. Accordingly, the lens surface in a lens cross-section alongone direction changes to have a curvature; however, the lens surface isa straight line in a lens cross-section along the cross-section of theother direction which intersects orthogonally with this direction. Inpractice, in the cylindrical lenses which are arranged in the firstsecond region A2-1 and the third second region A2-3, the lens surface(the surface of the concave section 12) changes to have a curvaturealong the X axis and incident light from the Z axis direction isconcentrated on the first region A1 side; however, the lens surface (thesurface of the concave section 12) is a straight line along the Y axis.In addition, in the cylindrical lenses which are arranged in the secondsecond region A2-2 and the fourth second region A2-4, the lens surface(the surface of the concave section 12) changes to have a curvaturealong the Y axis and incident light from the Z axis direction isconcentrated on the first region A1 side; however, the lens surface (thesurface of the concave section 12) is a straight line along the X axis.

The light path of the incident light which is incident on the thirdregion and in parallel with the normal line of the cell CL is bent tothe first region A1 side by the spherical lens. The spherical lens whichis arranged in the third region is a convex lens, the thickness of thespherical lens (the thickness of the second transparent material 13) isthe maximum at the intersection of the first region A1, and thespherical lens becomes thinner further from the intersection of thefirst region A1. In detail, the thickness of the spherical lens (thethickness of the second transparent material 13) is the maximum at thefirst intersection AC1 in the spherical lens which is arranged in thefirst third region A3-1, the thickness of the spherical lens (thethickness of the second transparent material 13) is the maximum at thesecond intersection AC2 in the spherical lens which is arranged in thesecond third region A3-2, the thickness of the spherical lens (thethickness of the second transparent material 13) is the maximum at thethird intersection AC3 in the spherical lens which is arranged in thethird third region A3-3, and the thickness of the spherical lens (thethickness of the second transparent material 13) is the maximum at thefourth intersection AC4 in the spherical lens which is arranged in thefourth third region A3-4.

As shown in FIG. 5, the length of a diagonal line of the cell CL is setas P1 and the length of a side of the cell CL in the X direction is setas P2. The arrangement pitch of the cell CL in the X direction is P2.For example, when the planar shape of the cell CL is a square and thearrangement pitch P2 of the cell CL is 10 μm, the length P1 of thediagonal line of the cell CL is approximately 14 μm. A direction alongthe diagonal line of the cell CL is set as a W direction. The Wdirection is a direction which intersects with the X direction and the Ydirection in a plane which is configured by the X direction and the Ydirection.

As shown in FIG. 5, the concave section 12 of the microlens ML has thefirst region A1 (the flat section 12 a) which is arranged in the centralportion, the curved surface section 12 b which is arranged in theperiphery of the flat section 12 a, and the periphery section 12 c whichis arranged in the periphery of the curved surface section 12 b. Thesecond region and the third region include the curved surface section 12b and the periphery section 12 c. The flat section 12 a, the curvedsurface section 12 b, and the periphery section 12 c are continuouslyformed. The first region A1 (the flat section 12 a) is a rectangle andthe intersections in the present embodiment are the four corners of therectangular shape of the flat section 12 a; however, the intersectionsmay be formed in an arc shape. The curved surface section 12 b and theperiphery section 12 c are formed in a rectangular planar shape in thesecond region and are concentrically formed centering on theintersection in the third region. Here, the length of the diagonal lineof the first region A1 is represented by R1, the width of the curvedsurface section 12 b is represented by R2, the maximum width of theperiphery section 12 c is represented by R3, and the width of theperiphery section 12 c in the second region is represented by R4. In thepresent embodiment, since the planar shape of the flat section 12 a is asquare, the length of the flat section 12 a in the X direction and the Ydirection is R1/√2. The length of the cell CL in the X direction and theY direction is P2=P1/√2 and is in a range from approximately 4.0 μm to30 μm. It is preferable that R1/√2 μm be in a range from 1.0 μm to lessthan 30 μm with respect to such a cell. Here, in the present embodiment,P1=22 μm, R1+2×(R2+R3)=20 μm, and a depth D (refer to FIGS. 6A and 6B)of the microlens ML is D=4.6 μm.

In the microlens array 10, the plurality of the concave sections 12 arearranged such that the concave sections 12 which are adjacent in the Xdirection and the Y direction come into contact with each other.Accordingly, the concave sections 12 which are adjacent in the Xdirection and the Y direction are connected with each other. On theother hand, the concave sections 12 which are adjacent in the Wdirection are separated from each other. The separating section is theupper surface 11 a. The microlens array 10 is manufactured by isotropicetching with respect to the first transparent material 11, which has themeaning that a virtual etching surface EF at that time is larger thanthe cell CL apart from the vicinity of the cell corner section. Thevirtual etching surface EF is a length of R2+R3 from each of the regionboundaries or the intersections in the first region A1. Accordingly, inthe microlens ML, a relationship of R2+R4<R2+R3<(P1−R1)/2 is satisfied.

As shown in FIGS. 6A and 6B, the flat section 12 a is a substantiallyflat surface substantially parallel with the upper surface 11 a of thefirst transparent material 11. The flat section 12 a does not have alight concentration function as a lens. Therefore, light which incidenton the flat section 12 a along the normal line direction of the uppersurface 11 a is straight as is. In the case of an electro-optical devicewhich uses the microlens ML, since light which is incident on the flatsection 12 a which is positioned in the central portion of the pixel Pis not shielded by the light shielding layer 26 (refer to FIG. 3) evenwhen going straight as is, the light may not be concentrated to thecenter side of the pixel P.

In addition, by not concentrating the light which is incident on theflat section 12 a to the planar center side of the pixel P, variationsin the angle of the light which passes through the liquid crystal 40(refer to FIG. 3) in the central portion of the pixel P are suppressedcompared to the microlens ML which has the concave section 12 which issubstantially spherical in the related art and which has a lightconcentration function over the whole region (refer to FIGS. 7B and 7C).Due to this, since the variations in the angle of the light with respectto the oriented direction of the liquid crystal molecules of the liquidcrystal 40 are suppressed to be small, the contrast of the liquidcrystal device 1 improves.

The curved surface section 12 b is provided to continue from the flatsection 12 a and has a cross-section shape in the form of an arc. Thecurved surface section 12 b has a light concentration function as a lensand light which is incident on the curved surface section 12 b along thenormal line direction of the upper surface 11 a is concentrated to theplanar center side of the cell CL. Accordingly, due to the curvedsurface section 12 b, it is possible to make the light, which isincident outside of the central portion of the pixel P and which isshielded by the light shielding layer 26 when going straight as is inthe electro-optical device, incident inside the opening region of thepixel P.

The periphery section 12 c is provided to continue from the curvedsurface section 12 b. The periphery section 12 c is connected with theupper surface 11 a in the W direction and connected with the peripherysection 12 c of the concave section 12 which is adjacent in the Xdirection. The periphery section 12 c is an inclined surface which isinclined from the upper surface 11 a toward the curved surface section12 b, a surface with a so-called tapered shape. Accordingly, since thelight which is incident on the periphery section 12 c along the normalline direction of the upper surface 11 a is refracted to the planarcenter side of the cell CL, it is possible to make the light, which isshielded by the light shielding layer 26 when going straight as is inthe electro-optical device, incident inside the opening region of thepixel P.

In addition, the periphery section 12 c does not have a lightconcentration function as a lens. Accordingly, since the light which isincident on the periphery section 12 c along the normal line directionof the upper surface 11 a is refracted at substantially the same angle,it is possible to suppress the variations in the angle of the lightwhich is incident on the liquid crystal 40.

Principle

FIGS. 7A to 7C are diagrams which illustrate the light utilizationefficiency in an electro-optical device, FIG. 7A is a case of using themicrolens according to the present embodiment, and FIGS. 7B and 7C arecases of using the microlens according to comparative examples whichcorrespond to the techniques in the related art. Next, description willbe given of the microlens ML according to the present embodimentimproving the light utilization efficiency with reference to FIGS. 7A to7C. Here, FIGS. 7B and 7C are the techniques in the related art;however, in order to facilitate understanding of the description, thesame names, reference numbers, and reference numerals as the presentembodiment are also used for the elements or the configurationrequirements of the techniques in the related art.

As shown in FIG. 6A, when the angle between the periphery section 12 cand the upper surface 11 a is set as θ, it is preferable that θ be inthe range from 35° to 53°, and θ=37° in the present embodiment. On theother hand, in the spherical shape microlens ML in the related art, theperiphery section 12 c is not present and the angle between a tangentialline of the curved surface section 12 b and the upper surface 11 a inthe end section of the microlens ML is an angle close to 90°. When theangle θ between the curved surface section 12 b and the upper surface 11a is large, the light which is incident on the curved surface section 12b along the normal line direction of the upper surface 11 a is greatlyrefracted. When the refractive angle of light is large, the refractedlight is shielded by the light shielding layer 22 a or the lightshielding layer 26 a between adjacent pixels P and the light utilizationefficiency does not improve. Thus, in the related art technique shown inJP-A-2004-70282, a lens in which the central portion is spherical andthe surrounding section is a circular truncated cone is used as shown inFIG. 7B or 7C.

According to diligent research by the present inventors, the reason thatthe light utilization efficiency is low in an electro-optical devicewhich uses the microlens ML of the related art is described as below.That is, in a case in which a pixel size in the electro-optical devicewhich uses the microlens array 10 as described in JP-A-2004-70282 is aslarge as 20 μm or longer, as shown in FIG. 7C, when the microlens ML isdesigned such that the incident light L2 which is incident on thesurrounding section of the microlens ML is incident on the projectorlens 117, there are times when the incident light L3 which is incidentin the vicinity of the central portion is not incident on the projectorlens 117. In contrast, in a case in which the pixel size in theelectro-optical device which uses the microlens array 10 as described inJP-A-2004-70282 is as small as 10 μm or shorter, as shown in FIG. 7B,when the microlens ML is designed such that the incident light L2 whichis incident on the surrounding section of the microlens ML is incidenton the projector lens 117, there are times when the incident light L3which is incident in the vicinity of the central section is shielded bythe light shielding layer 22 a or the light shielding layer 26 a. Withrespect to this, as shown in 7A, the light utilization efficiency isincreased in the microlens array 10 according to the present embodimentsince the pixel size is in a wide range from 4.0 μm to 30 μm, theincident light L1 which is incident on the central portion of themicrolens ML or the incident light L3 which is incident in the vicinityof the central portion is straight, and the light which is incident onthe surrounding section (the second region or the third region) of themicrolens is concentrated by a plurality (four in the presentembodiment) of cylindrical lenses and a plurality (four in the presentembodiment) of spherical lenses.

In this manner, according to the configuration of the microlens ML withwhich the microlens array 10 according to Embodiment 1 is provided,compared to the microlens in the related art, the size of the pixel Phas a wide range and it is possible to improve the light utilizationefficiency of the liquid crystal device 1. In addition, compared to themicrolens in the related art, it is possible to suppress the variationsin the angle of the light which passes through the microlens ML andwhich is incident on the liquid crystal 40 to be small. Due to this, itis possible to obtain a brighter display and a more favorable contrastthan in the related art.

Ratio of First Region in Cell

FIG. 8 is a diagram which illustrates the light utilization efficiencyin the microlens according to Embodiment 1. Next, description will begiven of a relationship between the ratio of the first region A1 in thecell and the light utilization efficiency in the microlens ML accordingto the present embodiment with reference to FIG. 8.

FIG. 8 is a graph which compares the light utilization efficiencyaccording to a pixel pitch (P2) by simulation when the size of the firstregion A1 (the flat section 12 a) is differentiated in the microlens MLaccording to Embodiment 1 by setting the spherical microlens in therelated art as a reference. The horizontal axis in FIG. 8 shows a ratioof the flat section 12 a in the pixel P and in detail, a ratio of thediagonal length R1 of the first region A1 (the flat section 12 a) withrespect to the pixel pitch (P2). Below, the ratio is referred to as theopening ratio. The vertical axis in FIG. 8 is the light utilizationefficiency and the spherical microlens (which does not have a flatsection) of the related art is set to “1”. Here, the “light utilizationefficiency” described here indicates the brightness of an image which isdisplayed on a screen using the liquid crystal device 1 which isprovided with the microlens ML as a liquid crystal light bulb of aprojector.

In a case in which the pixel pitch is as small as 8.5 μm, the lightutilization efficiency when the opening ratio is 20% to 45% improvescompared to the spherical lens. This is because, even in a small pixelP, the light shielding layer 22 a or the light shielding layer 26 a suchas the wiring width is the same as a wide pixel P and the importance ofthe spherical lens increases since the opening region of the pixel P isnarrowed in the small pixel P. Although not shown in the diagram, in acase in which the pixel pitch is smaller than 4.0 μm, the effect of theflat section 12 a is hardly seen.

In a case in which the pixel pitch is as large as 21.0 μm, the lightutilization efficiency improves compared to the spherical lens when theopening ratio is 20% to 110%. This is because the importance of thespherical lens decreases since the opening region of the pixel P is widein the big pixel P. In a case in which the pixel pitch is wider than 30μm, the importance of the microlens is small. That is, in the microlensML according to Embodiment 1, in a case in which the pixel pitch islarge, it is possible to obtain a higher light utilization efficiencythan with the spherical microlens of the related art.

Method for Manufacturing an Electro-Optical Device

FIGS. 9A to 9D are schematic cross-sectional diagrams which show amethod for manufacturing the microlens array according to Embodiment 1.FIGS. 10A to 10C are schematic cross-sectional diagrams which show amethod for manufacturing the microlens array according to Embodiment 1.In detail, each diagram of FIGS. 9A to 9D and FIGS. 10A to 10Ccorresponds to the schematic cross-sectional diagram taken along lineIXA-IXA, IXB-IXB, IXC-IXC, IXD-IXD and XA-XA, XB-XB, XC-XC in FIG. 4 andFIG. 5. Next, description will be given of a method for manufacturingthe liquid crystal device 1 which has the microlens array 10 accordingto Embodiment 1 with reference to FIGS. 9A to 9D and FIGS. 10A to 10C.Here, in FIGS. 9A to 9D and FIGS. 10A to 10C, in order to facilitateunderstanding of the description, a cross-sectional diagram is drawnwhich corresponds to three microlenses ML when the microlens array 10 iscompleted. In addition, although not shown in the diagram, in theprocess of manufacturing the microlens array 10, processing is performedon a large substrate (a mother substrate) which is able to take aplurality of microlens arrays 10 and the plurality of the microlensarrays 10 are obtained by finally cutting and individuating the mothersubstrate. Accordingly, the processing is performed in a state beforethe mother substrate is individuated in each of the processes describedbelow; however, here, description will be given of processing withrespect to the individual microlens array 10 in the mother substrate.

Firstly, a process of forming the first transparent material 11 on asubstrate is performed. In the present embodiment, since a quartzsubstrate serves as a portion of the first transparent material 11, thisprocess is a process of preparing the quartz substrate and, as shown inFIG. 9A, a process of forming a control film 70 formed of a siliconoxide film or the like on the upper surface 11 a of the firsttransparent material 11. The control film 70 has a different etchingrate from the quartz substrate when forming the concave section 12 andhas a function of adjusting the etching rate in the width direction (theW direction) with respect to the etching rate in the depth direction(the Z direction) when forming the concave section 12. When the etchingrate of the control film 70 is fast, the angle θ is small, the curvedsurface section 12 b is small (R2 is short), and the periphery section12 c is large (R3 is long). When the etching rate of the control film 70is the same as the quartz substrate, since the angle θ is 90° and theperiphery section 12 c disappears (R3 is zero), it is necessary that theetching rate of the control film 70 be slower than the etching rate ofthe quartz substrate.

After forming the control film 70, annealing of the control film 70 isperformed at a predetermined temperature. The etching rate of thecontrol film 70 changes according to the temperature during theannealing. Accordingly, it is possible to adjust the etching rate of thecontrol film 70 by appropriately setting the temperature during theannealing.

Next, as shown in FIG. 9B, a process of forming the mask layer 71 whichhas an opening section in the unit region on the control film 70 of thefirst transparent material 11 proceeds. The unit region is a regionwhich is a cell CL when the microlens array 10 is completed. The masklayer 71 is, for example, formed of polycrystal silicon or the like onthe upper surface of the first transparent material 11. The polycrystalsilicon which forms a mask layer is, for example, accumulated by achemical vapor deposition method (CVD), a physical vapor depositionmethod (for example, a sputtering method or the like), or the like.Subsequently, as shown in FIG. 9C, a photolithography method and a dryetching process are carried out on the accumulated thin films and themask layer 71 which has the opening section 72 is formed. The openingsection 72 is the same planar shape as the flat section 12 a in planview when the microlens array 10 is completed. Accordingly, the openingsection 72 is a polygon in plan view and at least one side which formsthe unit region and at least one side which forms the opening section 72are substantially parallel in plan view.

Next, as shown in FIG. 9D, by carrying out the isotropic etching on thecontrol film 70 and the first transparent material 11 via the masklayer, a process of forming the concave section 12 on the control film70 and the first transparent material 11 proceeds. That is, for example,an isotropic etching process such as wet etching which uses an etchantsuch as a hydrofluoric acid solution is carried out on the firsttransparent material 11 via the mask layer. A material for which theetching rate of the control film 70 is larger than the etching rate ofthe first transparent material 11 as described above is used for theetchant. Due to the etching process, the first transparent material 11is isotropically etched from the upper surface side by setting theopening section as a center. As a result, the concave section 12 isformed in the control film 70 and the first transparent material 11 incorrespondence with the opening section. As shown in FIG. 10A, theconcave section 12 is enlarged along with the progress of the isotropicetching and a portion which corresponds to the opening section 72 of themask layer 71 in plan view out of the concave section 12 is asubstantially flat surface. Due to this, the flat section 12 a is formedin the central portion of the concave section 12. In addition, thecurved surface section 12 b is formed so as to surround the periphery ofthe flat section 12 a. When the control film 70 is not provided betweenthe first transparent material 11 and the mask layer 71, the curvedsurface section 12 b reaches the upper surface 11 a of the firsttransparent material 11. However, in the present embodiment, the controlfilm 70 is provided between the first transparent material 11 and themask layer 71 and the etching amount of the control film 70 for eachunit of time is more than the etching amount of the first transparentmaterial 11 for each unit of time. Accordingly, since the enlargementamount of the opening section 70 a of the control film 70 is more thanthe enlargement amount of the concave section 12 in the depth direction,the width direction of the concave section 12 is also enlarged alongwith the enlargement of the opening section 70 a. Therefore, the etchingamount of the first transparent material 11 in the width direction foreach unit of time is more than the etching amount in the depth directionfor each unit of time. Due to this, the periphery section 12 c with atapered shape is formed so as to surround the periphery of the curvedsurface section 12 b.

As described above, it is possible to control the shape of the flatsection 12 a in the concave section 12 according to the shape of theopening section 72 of the mask layer 71. In addition, the respectivesizes of the curved surface section 12 b and the periphery section 12 cin the concave section 12 are controlled according to the etching ratein the width direction of the first transparent material 11 with respectto the etching rate in the depth direction and it is possible to adjustthe difference between the etching rates by setting the temperatureduring the annealing of the control film 70.

Next, as shown in FIG. 10B, after removing the mask layer 71 from thefirst transparent material 11, a process of forming the secondtransparent material 13 which has a higher refractive index than thefirst transparent material 11 so as to cover the concave section 12proceeds. That is, a process of filling the concave section 12 with thesecond transparent material 13 which has a refractive index which isdifferent from the refractive index of the first transparent material 11proceeds. Firstly, the second transparent material 13 formed of aninorganic material which has a light transmitting property and which hasa higher refractive index than the first transparent material 11 isfilm-formed so as to fill the concave section 12 by covering the entireregion of the first transparent material 11. It is possible to form thesecond transparent material 13, for example, using a CVD method. Sincethe second transparent material 13 is formed so as to be accumulated onthe upper surface of the first transparent material 11, the surface ofthe second transparent material 13 has an uneven shape in whichunevenness caused by the concave section 12 of the first transparentmaterial 11 is reflected. After accumulating the second transparentmaterial 13, a planarizing process is carried out with respect to thefilm. In the planarizing process, for example, the upper surface of thesecond transparent material 13 is planarized by polishing and removingthe portion of the upper layer of the second transparent material 13 inwhich the unevenness is formed using a chemical mechanical polishingmethod or the like. That is, by polishing and removing the portion abovethe two dotted line shown in FIG. 10B, the upper surface of the secondtransparent material 13 is planarized. Thus, as shown in FIG. 10C, theupper surface of the second transparent material 13 is planarized andthe microlens array 10 is completed.

Next, using a technique which is known in the art, the counter substrate30 is obtained by forming the light path length adjusting layer 31, thelight shielding layer 32, the protective layer 33, the common electrode34, and the oriented film 35 in sequence on the microlens array 10.Description will be given of the subsequent processes with reference toFIG. 3, but detailed illustration will be omitted. Meanwhile, theelement substrate 20 is obtained by forming the light shielding layer22, the insulation layer 23, the TFT 24, the insulation layer 25, thelight shielding layer 26, the insulation layer 27, the pixel electrode28, and the oriented film 29 in sequence on the substrate 21.

Next, as the sealing material 42 (refer to FIG. 1), a thermosetting orphotocurable adhesive agent is arranged and cured between the elementsubstrate 20 and the counter substrate 30. Due to this, the elementsubstrate 20 and the counter substrate 30 are bonded and the liquidcrystal device 1 is completed.

Electronic Apparatus

Next, description will be given of an electronic apparatus withreference to FIG. 11. FIG. 11 is a schematic diagram which shows aconfiguration of a projector as an electronic apparatus according toEmbodiment 1.

As shown in FIG. 11, the projector (the projection type displayapparatus) 100 as the electronic apparatus according to Embodiment 1 isprovided with a polarization lighting apparatus 110, two dichroicmirrors 104 and 105, three reflection mirrors 106, 107, and 108, fiverelay lenses 111, 112, 113, 114, and 115, three liquid crystal lightbulbs 121, 122, and 123, a cross dichroic prism 116, and the projectorlens 117.

The polarization lighting apparatus 110 is, for example, provided with alamp unit 101 as a light source formed of a white light source such asan ultrahigh pressure mercury lamp or a halogen lamp, an integrator lens102, and a polarization conversion element 103. The lamp unit 101, theintegrator lens 102, and the polarization conversion element 103 arearranged along a system optical axis Lx.

The dichroic mirror 104 reflects a red light (R) out of the polarizationluminous flux which is output from the polarization lighting apparatus110 and transmits a green light (G) and a blue light (B). The otherdichroic mirror 105 reflects the green light (G) which is transmittedthrough the dichroic mirror 104 and transmits the blue light (B).

The red light (R) which is reflected by the dichroic mirror 104 isincident on the liquid crystal light bulb 121 via the relay lens 115after being reflected by the reflection mirror 106. The green light (G)which is reflected by the dichroic mirror 105 is incident on the liquidcrystal light bulb 122 via the relay lens 114. The blue light (B) whichis transmitted through the dichroic mirror 105 is incident on the liquidcrystal light bulb 123 via an optical guiding system which is configuredby the three relay lenses 111, 112, and 113 and the two reflectionmirrors 107 and 108.

The transmission type liquid crystal light bulbs 121, 122, and 123 asoptical modulators are respectively arranged to oppose the incidentsurface for each colored light of the cross dichroic prism 116. Thecolored light which is incident on the liquid crystal light bulbs 121,122, and 123 is modulated based on video information (a video signal)and is output toward the cross dichroic prism 116.

The cross dichroic prism 116 is configured by bonding four rectangularprisms and a dielectric multilayer film which reflects the red light anda dielectric multilayer film which reflects the blue light are formed ina cross shape on the inner surface thereof. Light which represents acolor image is synthesized by the three colored lights being synthesizedby the dielectric multilayer films. The synthesized light is projectedon a screen 130 by the projector lens 117 which is a projection opticalsystem and the image is enlarged and displayed.

The liquid crystal device 1 described above is applied to the liquidcrystal light bulb 121. The liquid crystal light bulb 121 is arranged byplacing an interval between a pair of polarization elements which arearranged in a crossed nicol state on the incident side and the outputside of the colored light. The other liquid crystal light bulbs 122 and123 are the same.

According to the configuration of the projector 100 according toEmbodiment 1, it is possible to provide the projector 100 which isbright and of high quality even when a plurality of the pixels P arearranged with high definition since the liquid crystal device 1 whichhas the microlens ML which is able to efficiently use the incidentcolored light is provided.

The invention is not limited to the embodiments described above and itis possible to add various types of changes or improvements to theembodiments described above within a range which does not depart fromthe gist of the invention. For example, the invention is able to beapplied even to a form with a configuration in which the flat section 12a of the first region A1 has a curvature.

What is claimed is:
 1. A lens array comprising: a base which has aplurality of concave sections, the concave sections being arranged in afirst direction, a second direction which is orthogonal or almostorthogonal with the first direction, and a third direction whichintersects with the first direction and the second direction, wherein athickness of the base between the concave sections arranged in the firstdirection or the second direction is thinner than a thickness of thebase between the concave sections arranged in the third direction, andwherein each of the plurality of concave sections includes a flatsection substantially parallel to a surface of the base.
 2. The lensarray according to claim 1, further comprising: a transparent layerwhich covers a surface of the base provided with the plurality ofconcave sections, wherein a thickness of the transparent layer coveringthe base at a boundary between the concave sections arranged in thefirst direction or the second direction is thicker than a thickness ofthe transparent layer covering the base at a boundary between theconcave sections arranged in the third direction.
 3. The lens arrayaccording to claim 2, further comprising a light path length adjustinglayer which covers the transparent layer from an opposite side of thesurface.
 4. An electro-optical device comprising the lens arrayaccording to claim
 3. 5. An electro-optical device comprising the lensarray according to claim
 2. 6. An electro-optical device comprising thelens array according to claim
 1. 7. A lens array comprising: a basewhich has a plurality of concave sections, the concave sections beingarranged in a first direction, a second direction which is orthogonal oralmost orthogonal with the first direction, and a third direction whichintersects with the first direction and the second direction; and atransparent layer which covers a surface of the base provided with theplurality of concave sections, wherein a thickness of the transparentlayer covering the base at a boundary between the concave sectionsarranged in the first direction or the second direction is thicker thana thickness of the transparent layer covering the base at a boundarybetween the concave sections arranged in the third direction, andwherein each of the plurality of concave sections includes a flatsection substantially parallel to a surface of the base.
 8. The lensarray according to claim 7, wherein a thickness of the base between theconcave sections arranged in the first direction or the second directionis thinner than a thickness of the base between the concave sectionsarranged in the third direction.
 9. An electro-optical device comprisingthe lens array according to claim
 8. 10. The lens array according toclaim 7, further comprising a light path length adjusting layer whichcovers the transparent layer from an opposite side of the surface. 11.An electro-optical device comprising the lens array according to claim10.
 12. An electro-optical device comprising the lens array according toclaim 7.